Coway are some of the best, and there are many dumb models without internet access at all

If you don't mind the hum of fans, it's hard to beat a Corsi-Rosenthal box... there are kits from cleanairkits.com or cybernightmarket.com to build quiet PC fan based boxes that in my experience work excellent and can use off-the shelf filters and parts

I have a dumb model (1512HH) and it’s excellent.